Hydrocephalus is a group of diseases that can be caused by a variety of factors. The main principle is that the circulatory pathway of cerebrospinal fluid is blocked or there is excessive production and insufficient absorption, resulting in excessive accumulation of cerebrospinal fluid in the ventricles of the brain, causing a series of clinical symptoms. Hydrocephalus can develop at any age, but it is more common in infants and the elderly. In addition to the etiology and history of hydrocephalus, the diagnosis of hydrocephalus depends mainly on imaging examinations. CT and MRI are both commonly used imaging examinations, and MRI is clearer than CT and can determine the situation in the brain more clearly and accurately. Especially after hydrocephalus, in addition to observing the degree of ventricular enlargement, it can also observe whether there is cerebrospinal fluid infiltration and cerebral white matter demyelination around the ventricles, and observe whether there are arachnoid adhesions, which can help further determine the cause of hydrocephalus.